Interest in the characterization of nanoparticles, aerosols and dusts continues to increase, but typical tools and devices are not capable of manipulation and analysis of single particles. Fields ranging from atmospheric chemistry to astrophysical phenomena to industrial applications would benefit from tools to analyze particles with the capability of analyzing single particles and their impact dynamics.
Much early research focused on theoretical modeling of nanoparticle and microparticle collisions. Electrostatic accelerators were then recognized as a tool to manipulate small, easily charged microparticles. An early electrostatic accelerator for microparticle study was a 2 MV van de Graaff dust accelerator was described and shown to accelerate 1 μm particles to ˜6 km/s. See, e.g., Friichtenicht J F., “Two-million-volt electrostatic accelerator for hypervelocity research,” Rev Sci Instrum. 1962; 33:209-12. Friichtenicht J F. Micrometeoroid simulation using nuclear accelerator techniques. Nucl Inst Meth. 1964; 28:70-8. One early example of a switched, multistage linear accelerator for microparticles is described by Vedder. Vedder J F, “Microparticle accelerator of unique design,” Rev Sci Instrum. 1978; 49:1-7. Such microparticle accelerators benefitted from advances in laboratory-scale linear accelerators, such as the accelerator described by Hendell and Even. Hendell E, Even U. Tabletop linear accelerator for massive molecules. Rev Sci Instrum. 1995; 66:3901-2.
Mass spectrometric measurements on single charged nanoparticles can be conducted via charge detection mass spectrometry (CDMS) techniques. Benner W H., “A gated electrostatic ion trap to repetitiously measure the charge and m/z of large electrospray ions,” Anal Chem. 1997; 69:4162-8. CDMS determines the absolute charge on a particle from the magnitude of the image charge induced on a pickup electrode when a charged particle passes through. The image charge waveform also yields the particle time-of-flight (TOF) and velocity through the pickup providing the mass-to-charge ratio for fixed energy particles. Gamero-Castaño M. Induction charge detector with multiple sensing stages. Rev Sci Instrum. 2007; 78:043301. State-of-the-art CDMS is capable of analysis of massive biomolecules, cells and nanoparticles, and can also conduct mass spectrometry measurements. See, e.g., Contino N C, Pierson E E, Keifer D Z, Jarrold M F, “Charge detection mass spectrometry with resolved charge states,” J Am Soc Mass Spec. 2013; 24:101-8. Keifer D Z, Shinholt D L, Jarrold M F, “Charge detection mass spectrometry with almost perfect charge accuracy,” Anal Chem. 2015; 87:10330-7; Keifer D Z, Jarrold M F, “Single-molecule mass spectrometry,” Mass Spec Rev. Volume 414, March 2017, Pages 45-55 (2016). As shown by Hendell and Even (Hendell E, Even U., “Tabletop linear accelerator for massive molecules,” Rev Sci Instrum. 1995; 66:3901-2), and later applied by Hsu and colleagues (Hsu Y-F, Lin J-L, Lai S-H, Chu M-L, Wang Y-S, Chen C-H. Macromolecular Ion Accelerator. Anal Chem. 2012; 84:5765-9), a linear accelerator for large molecular ions can be configured using modern high-voltage MOSFET switching techniques.